package com.lzy.shiro;

import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.lzy.common.lang.Result;
import com.lzy.util.JwtUtils;
import io.jsonwebtoken.Claims;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.ExpiredCredentialsException;
import org.apache.shiro.web.filter.authc.AuthenticatingFilter;
import org.apache.shiro.web.util.WebUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 请求头中是否存在token，并封装成JwtToken供AccountRealm使用
 * @autor shkstart
 * @create 2021-01-14 14:17)
 */
@Component
public class JwtFilter extends AuthenticatingFilter {
        @Autowired
        JwtUtils jwtUtils;

            /*
    *
    *   createToken：实现登录，我们需要生成我们自定义支持的JwtToken
        onAccessDenied：拦截校验，当头部没有Authorization时候，我们直接通过，不需要自动登录；
                   当带有的时候，首先我们校验jwt的有效性，没问题我们就直接执行executeLogin方法实现自动登录
        onLoginFailure：登录异常时候进入的方法，我们直接把异常信息封装然后抛出
        preHandle：拦截器的前置拦截，因为我们是前后端分析项目，项目中除了需要跨域全局配置之外，我们再拦截器中也需要提供跨域支持。这样，拦截器才不会在进入Controller之前就被限制了。
    * */

        @Override
        protected AuthenticationToken createToken(ServletRequest servletRequest, ServletResponse servletResponse) throws Exception {
            // 获取 token
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            String jwt = request.getHeader("Authorization");
            if(StringUtils.isEmpty(jwt)){
                return null;
            }
            return new JwtToken(jwt);
        }
        @Override
        protected boolean onAccessDenied(ServletRequest servletRequest, ServletResponse servletResponse) throws Exception {
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            String token = request.getHeader("Authorization");
            if(StringUtils.isEmpty(token)) {
                return true;
            } else {
                // 判断是否已过期
                Claims claim = jwtUtils.getClaimByToken(token);
                if(claim == null || jwtUtils.isTokenExpired(claim.getExpiration())) {
                    throw new ExpiredCredentialsException("token已失效，请重新登录！");
                }
            }
            // 执行自动登录
            return executeLogin(servletRequest, servletResponse);
        }
        @Override
        protected boolean onLoginFailure(AuthenticationToken token, AuthenticationException e, ServletRequest request, ServletResponse response) {
            HttpServletResponse httpResponse = (HttpServletResponse) response;
            try {
                //处理登录失败的异常
                Throwable throwable = e.getCause() == null ? e : e.getCause();
                Result r = Result.fail(throwable.getMessage());
                String json = JSONUtil.toJsonStr(r);
                httpResponse.getWriter().print(json);
            } catch (IOException e1) {
            }
            return false;
        }
        /**
         * 对跨域提供支持
         */
        @Override
        protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
            HttpServletRequest httpServletRequest = WebUtils.toHttp(request);
            HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
            httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
            httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
            httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
            // 跨域时会首先发送一个OPTIONS请求，这里我们给OPTIONS请求直接返回正常状态
            if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
                httpServletResponse.setStatus(org.springframework.http.HttpStatus.OK.value());
                return false;
            }
            return super.preHandle(request, response);
        }



    }

